Deck Sinking - the cause

As I started to dig under the post to make room for pouring a concrete footing, I discovered the cause of the deck sinkage.
The post was seated atop a rotting piece of old railroad tie buried under about 4 inches of dirt. The post was not even a 4x4 post. It was a garden timber (smaller, rounded sides).
Even worse, there was hardly any concrete around the post - about a half inch on one side and none under the post.

UNBELIEVABLE! I cannot believe that someone could be so stupid to build a deck support this way!